During military field operations, a soldier in the field needs about 6.6 gallons (54.8 pounds) of water per day for drinking, personal hygiene, meal rehydration, and emergency medical treatment. The high risk of chemical and biological contamination and/or limited supply in locally available water near battlefields requires that a large quantity of water be transported to ensure its suitability for human consumption. The transport of such large amounts of water in support of field operations strains logistical resources. The need to transport water can be significantly reduced if water can be reclaimed and purified from alternate sources, such as engine exhaust, waste water from kitchens and showers, and human waste.
Diesel exhaust typically contains approximately 10% water vapor. Assuming that an army uses approximately 12 million gallons of fuel per week, 100% reclamation of water produced from fuel consumption could provide about 12 million gallons of water per week. By employing standard thermodynamic water condensation, only about 50% of the water in exhaust containing 10% water vapor can be condensed. Because the exhaust contains soot particles, trace hydrocarbons, and acid gases such as NO2 and SO2, these contaminants would also reside in the water collected using thermodynamic condensation. Removal of these contaminants from the condensed water would require a potentially large filtration train potentially encompassing a large portion of the cargo area of a transport vehicle, and require the transportation of replacement filters and parts. For practical purposes in military field operations, there is a need for an improved system for water collection with higher reclamation efficiency and a smaller size.